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                        列表渲染
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                        条件渲染
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                        <h2 id="&#x6761;&#x4EF6;&#x6E32;&#x67D3;">&#x6761;&#x4EF6;&#x6E32;&#x67D3;</h2>
<p>&#x6839;&#x636E;&#x6761;&#x4EF6;&#x6E32;&#x67D3;&#x4E0D;&#x540C;&#x7684;&#x7ED3;&#x6784;&#xFF0C;&#x5C31;&#x662F;&#x6761;&#x4EF6;&#x6E32;&#x67D3;&#xFF0C;&#x6761;&#x4EF6;&#x6E32;&#x67D3;&#x6709;&#x4E0B;&#x9762;&#x51E0;&#x79CD;&#x521B;&#x5EFA;&#x5F62;&#x5F0F;&#xFF1A;</p>
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<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">Loginstate</span>(<span class="hljs-params">props</span>)</span>{
    <span class="hljs-keyword">if</span>(props.isLogin==<span class="hljs-literal">true</span>){
        <span class="hljs-keyword">return</span> <span class="xml"><span class="hljs-tag">&lt;<span class="hljs-title">h2</span>&gt;</span>&#x6B22;&#x8FCE;&#x56DE;&#x6765;&#xFF01;<span class="hljs-tag">&lt;/<span class="hljs-title">h2</span>&gt;</span>
    }else{
        return <span class="hljs-tag">&lt;<span class="hljs-title">h2</span>&gt;</span>&#x8BF7;&#x767B;&#x5F55;&#xFF01;<span class="hljs-tag">&lt;/<span class="hljs-title">h2</span>&gt;</span> 
    }
}

ReactDOM.render(<span class="hljs-tag">&lt;<span class="hljs-title">Loginstate</span> <span class="hljs-attribute">isLogin</span>=<span class="hljs-value">{true}</span>/&gt;</span>,document.getElementById(&apos;root&apos;));
</span></code></pre>
<h4 id="&#x7EC4;&#x4EF6;&#x5185;&#x6839;&#x636E;&#x6761;&#x4EF6;&#x8FD4;&#x56DE;&#x4E0D;&#x540C;&#x5B50;&#x7EC4;&#x4EF6;">&#x7EC4;&#x4EF6;&#x5185;&#x6839;&#x636E;&#x6761;&#x4EF6;&#x8FD4;&#x56DE;&#x4E0D;&#x540C;&#x5B50;&#x7EC4;&#x4EF6;</h4>
<pre><code class="lang-javascript"><span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">Login</span>(<span class="hljs-params">props</span>)</span>{
    <span class="hljs-keyword">return</span> <span class="xml"><span class="hljs-tag">&lt;<span class="hljs-title">h2</span>&gt;</span>&#x6B22;&#x8FCE;&#x56DE;&#x6765;&#xFF01;<span class="hljs-tag">&lt;/<span class="hljs-title">h2</span>&gt;</span>
}
function Logout(props){
    return <span class="hljs-tag">&lt;<span class="hljs-title">h2</span>&gt;</span>&#x8BF7;&#x767B;&#x5F55;&#xFF01;<span class="hljs-tag">&lt;/<span class="hljs-title">h2</span>&gt;</span>
}
function Loginstate2(props){
    if(props.isLogin==true){
        return <span class="hljs-tag">&lt;<span class="hljs-title">Login</span> /&gt;</span>
    }else{
        return <span class="hljs-tag">&lt;<span class="hljs-title">Logout</span> /&gt;</span>
    }
}
ReactDOM.render(<span class="hljs-tag">&lt;<span class="hljs-title">Loginstate2</span> <span class="hljs-attribute">isLogin</span>=<span class="hljs-value">{true}</span>/&gt;</span>,document.getElementById(&apos;root&apos;));
</span></code></pre>
<h4 id="&#x548C;&#x8FD0;&#x7B97;&#x7B26;--&#x4E00;&#x8D77;&#x4F7F;&#x7528;">&#x548C;&#x8FD0;&#x7B97;&#x7B26; &amp;&amp; &#x4E00;&#x8D77;&#x4F7F;&#x7528;</h4>
<p>&#x201C;&amp;&amp;&#x201D;&#x7B26;&#x53F7;&#x5DE6;&#x8FB9;&#x662F;&#x6761;&#x4EF6;&#x8FD0;&#x7B97;&#x5F0F;&#x6216;&#x8005;&#x5E03;&#x5C14;&#x503C;&#xFF0C;&#x53F3;&#x8FB9;&#x662F;&#x7ED3;&#x6784;&#xFF0C;&#x5982;&#x679C;&#x5DE6;&#x8FB9;&#x4E3A;&#x771F;&#xFF0C;&#x5C31;&#x751F;&#x6210;&#x53F3;&#x8FB9;&#x7684;&#x7ED3;&#x6784;&#xFF0C;&#x5982;&#x679C;&#x4E3A;&#x5047;&#xFF0C;&#x8FD9;&#x4E00;&#x53E5;&#x6574;&#x4F53;&#x5FFD;&#x7565;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">Notice</span> <span class="hljs-keyword">extends</span> <span class="hljs-title">React</span>.<span class="hljs-title">Component</span></span>{
    constructor(props){
        <span class="hljs-keyword">super</span>(props);
        <span class="hljs-keyword">this</span>.state={
            username:<span class="hljs-string">&apos;&#x5F20;&#x5927;&#x5C71;&apos;</span>,
            messages:[
                <span class="hljs-string">&apos;&#x65B0;&#x90AE;&#x4EF6;&apos;</span>,
                <span class="hljs-string">&apos;&#x65B0;&#x7684;&#x5F85;&#x529E;&apos;</span>
            ]
        }
    }
    render(){
        <span class="hljs-keyword">return</span>(
            <span class="xml"><span class="hljs-tag">&lt;<span class="hljs-title">div</span>&gt;</span>
                <span class="hljs-tag">&lt;<span class="hljs-title">h2</span>&gt;</span>&#x4F60;&#x597D;&#xFF0C;{this.state.username}<span class="hljs-tag">&lt;/<span class="hljs-title">h2</span>&gt;</span> 
                {
                    this.state.messages.length&gt;0 &amp;&amp; <span class="hljs-tag">&lt;<span class="hljs-title">p</span>&gt;</span>&#x4F60;&#x6709;{this.state.messages.length}&#x6761;&#x6D88;&#x606F;<span class="hljs-tag">&lt;/<span class="hljs-title">p</span>&gt;</span>
                }
            <span class="hljs-tag">&lt;/<span class="hljs-title">div</span>&gt;</span>
        )</span>
    }
}

ReactDOM.render(<span class="xml"><span class="hljs-tag">&lt;<span class="hljs-title">Notice</span> /&gt;</span>,document.getElementById(&apos;root&apos;));
</span></code></pre>

                    
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